This invention relates to devices for the treatment of heart disease and particularly to endow-arterial prostheses which are commonly called stints. More particularly, a catheter assembly is configured to retrieve a stent or other object from a vessel.
Several interventional treatment modalities are prestently used for heart disease including balloon and laser angioplasty, atherectomy and by-pass surgery. In typical balloon angioplasty procedures, a guiding catheter having a preformed distal tip is percutaneously introduced through the femoral artery into the cardiovascular system of a patient in a conventional Seldinger technique and advanced within the cardiovascular system until the distal tip of the guiding catheter is seated in the ostium of a desired coronary artery. A guide wire is positioned within an inner lumen of a dilatation catheter and then both are advanced through the guiding catheter to the distal end thereof. The guide wire is first advanced out of the distal end of the guiding catheter into the patient""s coronary vasculature until the distal end of the guide wire crosses a lesion to be dilated. Then the dilatation catheter having an inflatable balloon on the distal portion thereof is advanced into the patient""s coronary anatomy over the previously introduced guide wire until the balloon of the dilatation catheter is properly positioned across the lesion. Once in position across the lesion, the balloon which is made of relatively inelastic materials, is inflated to a predetermined size with radiopaque liquid at relatively high pressure (e.g., greater than 4 atmospheres) to press the arteriosclerotic plaque of the lesion against the inside of the artery wall and to otherwise expand the inner lumen of the artery. The balloon is then deflated so that blood flow can be resumed through the dilated artery and the dilatation catheter can be removed therefrom. Further details of dilatation catheters, guide wires, and devices associated therewith for angioplasty procedures can be found in U.S. Pat. No. 4,323,071 (Simpson-Robert); U.S. Pat. No. 4,439,185 (Lindquist); U.S. Pat. No. 4,516,972 (Samson); U.S. Pat. No. 4,538,622 (Samson et al.); U.S. Pat. No. 4,554,929 (Samson et al.); U.S. Pat. No. 4,616,652 (Simpson); U.S. Pat. No. 4,638,805 (Powell); and U.S. Pat. No. 4,748,982 (Horzewski etal.) which are hereby incorporated herein in their entirety by reference thereto.
One problem characteristic of balloon angioplasty procedures is the large number of patients who are subject to restenosis in the treated artery. In the case of restenosis, the treated artery may again be subjected to balloon angioplasty or to other treatments such as by-pass surgery if additional balloon angioplasty procedures are not warranted. However, in the event of a partial or total occlusion of a coronary artery by the collapse of a dissected arterial lining after the balloon is deflated, the patient is put in a situation requiring immediate medical attention, particularly in the coronary arteries.
A major focus of recent development work in the treatment of heart disease has been directed to endoprosthetic devices called stents. Stents are generally cylindrically shaped intravascular devices which are placed within a damaged artery to hold it open. The device can be used to prevent restenosis and to maintain the patency of blood vessels immediately after intravascular treatments. In some circumstances, they can also be used as the primary treatment device where they are expanded to dilate a stenosis and then left in place.
Two basic methods and systems have been developed for delivering stents to desired locations within body lumens. One method and system involves compressing or otherwise reducing the diameter of an expandable stent, disposing the compressed stent within a lumen provided in the distal end of a tubular catheter, advancing the catheter through the patient""s vasculature until the distal end of the catheter is immediately adjacent to the desired vascular location, and then pushing the stent out the distal end of the catheter into the desired location. Once out of the catheter, the compressed stent expands or is expanded to thereby hold open the artery or other body lumen into which it is placed.
Another method and system involves disposing a compressed or otherwise small diameter stent about an expandable member such as a balloon on the distal end of a catheter, advancing the catheter through the patient""s vascular system until the stent is in the desired location within a blood vessel and then expanding the expandable member on the catheter to expand the stent within the blood vessel. The expanded expandable member is then contracted and the catheter withdrawn, leaving the expanded stent within the blood vessel, holding open the passageway thereof.
Occasionally, a stent comes off of the catheter prior to expansion in the vessel, thereby embolizing in the vessel with no way to retrieve it. Likewise, a partially expanded stent may not stay expanded in the vessel and embolize. Other devices, such as embolic filters and the like, also may prematurely be dislodged from their delivery systems. In such cases, it is important to retrieve the stent or filter in order to reduce the likelihood of injury to the patient. Thus far, prior art devices have been unsuccessful in reliably locating and retrieving stents or filters for removal from the patient""s vascular system.
The prestent invention catheter retrieval system is configured for locating and reliably retrieving a stent or filter from a patient""s vascular system without injury to the patient.
The prestent invention provides for a reliable and safe apparatus and method for capturing and retrieving a stent, filter, or other device that has embolized in a patient""s vascular system. The prestent invention provides for an intravascular catheter having an inner member disposed within an outer member and having relative axial movement between the inner member and the outer member. A manipulating device or handle, operated by the physician, provides the relative axial movement between the inner member and the outer member. Disposed at the distal end of the inner member is a tube, such as a mesh braid, that is attached to the distal end of the inner member. The other end of the tube is attached to the distal end of the outer member. When the inner member is withdrawn proximally by the physician operating the manipulator, or handle, the tube reduces in size from a first enlarged diameter to a second compressed diameter.
The tube can be a typical mesh braid or similar mesh pattern made of stainless steel, nickel-titanium alloys, Elgiloy, or a polymer. The proximal end of a tube is attached to the distal end of the inner member by an adhesive, laser welding, or the like. Likewise, the distal end of the tube is preferably wrapped around the outside of the distal end of the outer member and attached by an adhesive, laser welding, or similar attachment means.
In the method of using the invention, the catheter, preferably a catheter of the rapid-exchange type, is advanced over a previously positioned guide wire. The guide wire preferably is threaded through the stent or filter that has embolized in the patient""s vascular system. As the catheter is advanced, the distal end of the outer member and the tube are advanced over the stent or filter. In order to capture the stent, the inner member is then withdrawn proximally by the physician operating the manipulator in order to cause the tube to compress from its first expanded diameter to its second compressed diameter. As the tube collapses, it tightly grips the stent or filter so that the stent is captured and can be removed from the patient. The catheter assembly and guide wire are withdrawn from the patient, or if another procedure is required, the guide wire can be left in the patient""s vascular system and the catheter removed in a rapid-exchange manner. Alternatively, over-the-wire or other similar catheter systems can be used with the prestent invention.